diff --git a/Gulpfile.js b/Gulpfile.js
index 063e558..7c7dace 100644
--- a/Gulpfile.js
+++ b/Gulpfile.js
@@ -5,7 +5,7 @@ var fs = require('fs');
 var mocha = require('gulp-mocha');
 var istanbul = require('gulp-istanbul');
 var isparta = require('isparta');
-require('babel-core/register');
+
 
 gulp.task('download', function () {
   return request('http://wixtoolset.org/downloads/v3.11.0.129/wix311-binaries.zip').pipe(fs.createWriteStream('wixToolset.zip'));
@@ -16,12 +16,39 @@ gulp.task('getwix',['download'], function(){
    .pipe(unzip())
    .pipe(gulp.dest('./lib/wixFiles'));
 });
+var paths = {
+    server: {
+        scripts:  ['src/**/*.js'],
+        tests:    ['test/**/*.js'],
+        coverage: 'coverage/'
+    }
+};
+
+gulp.task('test-coverage-server', function(cb) {
+    var coverageDir = paths.server.coverage;
+    gulp.src(paths.server.scripts)
+        .pipe(istanbul({ // Covering files
+            instrumenter: isparta.Instrumenter,
+            includeUntested: true
+        }))
+        .pipe(istanbul.hookRequire()) // Force `require` to return covered files
+        .on('finish', function() {
+            gulp.src(paths.server.tests, {read: false})
+                .pipe(mocha({reporter: 'spec'}))
+                .pipe(istanbul.writeReports({
+                    dir: coverageDir,
+                    reportOpts: {dir: coverageDir},
+                    reporters: ['text', 'text-summary', 'json', 'html']
+                }))
+                .on('end', cb);
+        });
+});
 
 gulp.task('pre-test', function () {
-  return gulp.src('src/**/*.js')
+  return gulp.src(['src/CommandBuilder.js'])
     // Covering files
     .pipe(istanbul({
-      instrumenter: isparta.Instrumenter,
+    //  instrumenter: isparta.Instrumenter,
       includeUntested: true}
 
     ))
@@ -29,7 +56,7 @@ gulp.task('pre-test', function () {
     .pipe(istanbul.hookRequire());
 });
 
-gulp.task('test', function(){
+gulp.task('test',['pre-test'], function(){
   return gulp.src('test/unit/*.js')
   .pipe(mocha())
   .pipe(istanbul.writeReports());
diff --git a/package.json b/package.json
index 4243481..94bd6d3 100644
--- a/package.json
+++ b/package.json
@@ -9,9 +9,11 @@
   "scripts": {
     "compile": "babel src --out-dir lib",
     "coveralls": "cat ./coverage/lcov.info | coveralls",
-    "prepublish": "npm run compile"
+    "prepublish": "npm run compile",
+    "test": "./node_modules/.bin/isparta cover node_modules/mocha/bin/_mocha"
   },
   "dependencies": {
+    "child-process-promise": "^1.1.0",
     "lodash": "^4.6.1"
   },
   "devDependencies": {
diff --git a/src/CommandBuilder.js b/src/CommandBuilder.js
index 3e87bea..3a4c11f 100644
--- a/src/CommandBuilder.js
+++ b/src/CommandBuilder.js
@@ -3,12 +3,11 @@ var fs = require('fs'),
     _ = require('lodash'),
     path = require('path');
 
-
 var calculateCommands =  function(options){
   var commands = {
-    heatPath: options.heatPath || __dirname + "/wixFiles/heat.exe",
-    lightPath: options.lightPath || __dirname + "/wixFiles/light.exe",
-    candlePath: options.candlePath || __dirname + "/wixFiles/candle.exe"
+    heatPath: options.heatPath || path.normalize(__dirname + "/wixFiles/heat.exe"),
+    lightPath: options.lightPath || path.normalize(__dirname + "/wixFiles/light.exe"),
+    candlePath: options.candlePath || path.normalize(__dirname + "/wixFiles/candle.exe")
   }
   if(options.version){
     process.env.BUILD_VERSION = version;
diff --git a/src/exec.js b/src/exec.js
index fe4de5b..0efba27 100644
--- a/src/exec.js
+++ b/src/exec.js
@@ -5,9 +5,10 @@
 var fs = require('fs'),
     _ = require('lodash'),
     path = require('path'),
-    child_process = require('child_process');
+    commandBuilder = require('./CommandBuilder.js'),
+    spawn = require('child-process-promise').spawn;
 
-var processResults = function (stdout, stderr) {
+var processResults = function (stdout) {
     if(stdout && _.isArray(stdout)){
       _.chain(stdout)
       .filter((item)=>item && item.length > 0)
@@ -17,114 +18,54 @@ var processResults = function (stdout, stderr) {
     else if(stdout && _.isString(stdout) && stdout.length > 0){
       console.log(stdout);
     }
-    if(stderr && _.isString(stderr) && stderr.length > 0){
-      console.log(stderr);
-    }
 
 };
+
+var processError = function(err, cb){
+  console.log(err);
+  if(cb && _.isFunction(cb) && err){
+    cb(err)
+  }
+  else if(err){
+    throw err
+  }
+}
+
+var processConsole = function processConsole(childProcess) {
+  if(childProcess && childProcess.stdout){
+    childProcess.stdout.on('data', (data)=>processResults(data.toString()));
+  }
+  if(childProcess && childProcess.stderr){
+    childProcess.stderr.on('data', (data)=>processResults(data.toString()));
+  }
+
+};
+
 var main = function (options, callback) {
-    var heatFiles = options.heatFiles;
-    var candleFiles = options.candleFiles;
-    var lightFiles = options.lightFiles;
-    var heatCommands = options.heatCommands || null;
-    var candleCommands = options.candleCommands || null;
-    var lightCommands = options.lightCommands || null;
-    var heatPath = options.heatPath || __dirname + "/wixFiles/heat.exe";
-    var lightPath = options.lightPath || __dirname + "/wixFiles/light.exe";
-    var candlePath = options.candlePath || __dirname + "/wixFiles/candle.exe";
-    var cb = callback;
-    var version = options.version;
-    if(version){
-      process.env.BUILD_VERSION = version;
-    }
-    if(!heatCommands){
-            if(!heatFiles || !_.isArray(heatFiles) || heatFiles.length < 1 ){
-            throw "heat files are required if no commands are passed";
-        }
-         checkFiles(heatFiles);
-    }
-
-    if(!candleCommands){
-
-      if(!candleFiles || !_.isArray(candleFiles) || candleFiles.length < 1 ){
-          throw "candle files are required";
+  var commands = commandBuilder(options);
+  //todo redo this a little...
+  if(commands.heatCommands){
+    return spawn(commands.heatPath, commands.heatCommands)
+    .progress(processConsole)
+    .then(()=>spawn(commands.candlePath, commands.candleCommands))
+    .progress(processConsole)
+    .then(()=>spawn(commands.lightPath, commands.lightCommands))
+    .progress(processConsole)
+    .then(()=>{
+      if(callback && _.isFunction(callback)){
+        callback();
       }
-
-      checkFiles(candleCommands);
-
-    }
-
-    if(!lightCommands){
-
-      if(!lightFiles || !_.isArray(lightFiles) || lightFiles.length < 1 ){
-          throw "light files are required";
-      }
-
-      checkFiles(lightFiles);
-
-    }
-
-    return child_process.execFile(path.normalize(heatPath), heatCommands? heatCommands: _.map(heatFiles, (file)=>`@${path.normalize(file)}`), (err, stdout, stderr)=>{
-      processResults(stdout, stderr);
-      if(err){
-        if(cb){
-          return cb(err);
-        }else{
-          throw err;
-        }
-
-      }
-
-          return child_process.execFile(path.normalize(candlePath), candleCommands? candleCommands: _.map(candleFiles, (file)=>`@${path.normalize(file)}`), (err, stdout, stderr)=>{
-            processResults(stdout, stderr);
-            if(err){
-              if(cb){
-                return cb(err);
-              }else{
-                throw err;
-              }
-
-            }
-
-              return child_process.execFile(path.normalize(lightPath), lightCommands? lightCommands: _.map(lightFiles, (file)=>`@${path.normalize(file)}`), (err, stdout, stderr)=>{
-                processResults(stdout, stderr);
-                if(err){
-                  if(cb){
-                    return cb(err);
-                  }else{
-                    throw err;
-                  }
-
-                }
-                if(cb){
-                  return cb();
-                }
-
-              });
-
+    });
+  }
+  return spawn(commands.candlePath, commands.candleCommands)
+        .progress(processConsole)
+        .then(()=>spawn(commands.lightPath, commands.lightCommands))
+        .progress(processConsole)
+        .then(()=>{
+          if(callback && _.isFunction(callback)){
+            callback();
+          }
         });
-
-    });
-};
-
-var checkFiles = function(files){
-    _.each(files, (file)=>{
-        if(!checkFile(file)){
-            throw "error finding file" + file;
-        }
-    });
-};
-var checkFile = function (file) {
-    if (!file || file.length < 1) {
-        return false;
-    }
-    try {
-        fs.accessSync(path.normalize(file), fs.R_OK); //will error if doesnt exist
-        //todo async?
-        return true;
-    } catch (error) {
-        return false;
-    }
 };
 
 module.exports = main;
diff --git a/test/unit/CommandBuilder.test.js b/test/unit/CommandBuilder.test.js
index ccfcf7d..7400575 100644
--- a/test/unit/CommandBuilder.test.js
+++ b/test/unit/CommandBuilder.test.js
@@ -1,6 +1,6 @@
 var assert = require('chai').assert;
 var expect = require('chai').expect;
-var commandBuilder = require('../../src/CommandBuilder');
+var commandBuilder = require('../../src/CommandBuilder.js');
 
 
 describe('CommandBuilderWorks', function(){